1. Field of the Invention
The present invention relates generally to computer-assisted design (CAD) systems, and in particular, to a graph-based method for multi-bodied sweep terminations in a computer-implemented solid modeling system.
2. Description of the Related Art
Over the last decade, designers have changed their fundamental approach to graphics design, moving from two-dimensional (2D) drawing systems to three-dimensional (3D) solid modeling systems. New software makes solid modeling technology available and affordable to virtually anyone.
Solid modeling is a technique that allows designers to create dimensionally accurate 3D solid models in a 3D space represented within a computer, rather than traditional 2D drawings. 3D solid models include significantly more engineering data than 2D drawings, including the volume, bounding surfaces, and edges of a design.
With the graphics capabilities of today's computers, these 3D solid models may be viewed and manipulated on a monitor. In addition to providing better visualization, 3D solid models may be used to automatically produce 2D drawing views, and can be shared with manufacturing applications and the like.
Some 3D solid modeling systems generate parametric feature-based models. A parametric feature-based model is comprised of intelligent features, such as holes, fillets, chamfers, etc. The geometry of the parametric feature-based model is defined by underlying mathematical relationships (i.e., parameters) rather than by simple unrelated dimensions, which makes them easier to modify. These systems preserve design intent and manage it after every change to the model.
An operation often performed by solid modeling systems to create parametric feature-based models is a profile sweep. A user typically draws a planar, simple (not self-intersecting) profile of curves and then instructs the solid modeling system to sweep the profile along a specified path (e.g., linearly for extrusions and circularly for revolutions). The result of the profile sweep is a shaped solid body or part.
However, the termination of profile sweeps (including extrusions and revolutions as special cases) is a non-trivial operation. This is especially true when multiple bodies are involved in the termination. Consequently, there is a need in the art for new methods of handling the termination of profile sweeps for multiple bodies in a solid modeling system.